The present invention generally relates to manufacturing, remanufacturing or repairing replaceable imaging components, and more particularly to techniques for adjusting the signal level provided to or received from an imaging component, such as a xerographic toner cartridge.
In the imaging industry, there is a growing market for the remanufacture and refurbishing of various types of replaceable imaging cartridges such as toner cartridges, drum cartridges, inkjet cartridges, and the like. Imaging cartridges, once spent, are unusable for their originally intended purpose. Without a refurbishing process, they would simply be discarded, even though the cartridge itself may still have potential life. As a result, techniques have been developed specifically to address this issue. These processes may entail, for example, the disassembly of the various structures of the cartridge, replacing toner or ink, cleaning, adjusting or replacing any worn components and reassembling the cartridge.
The method of remanufacturing a toner cartridge is dependent upon the original design of the toner cartridge. Some remanufacturers contend that changes in the design of toner cartridges by the original equipment manufacturer (OEM) are done, at least in part, to defeat remanufacturing. Whether this reason for OEM design changes is true or not, it is true that changes in the design of a cartridge by the OEM create new difficulties for remanufacturers. Most of these difficulties center on disassembling the cartridge in a way that allows for fast and economical cleaning, replacing of worn components, and adding new toner.
A recent design change by the OEM in a cartridge called the HP 9000 has a dramatically different design from previous toner cartridges. The HP 9000 is substantially larger, holding much more toner than previous toner cartridge designs. The HP 9000 has end caps that are welded onto the full width of the toner cartridge. The end caps apparently give the cartridge greater strength, and help hold the toner hopper/developer roller housing/waste bin sub assembly. Before the introduction of the HP 9000 most toner cartridges had a toner hopper attached to a developer roller housing, and flexible film seal heat-sealed to the sealing surface of the toner hopper. The toner hopper/seal/developer roller housing assembly in turn was mechanically connected to the waste bin. The mechanical connection to the waste bin was accomplished with the use of one or more pins. The toner hopper was attached to the developer roller housing by ultrasonic welds at the seam between them. These welds were readily accessible from the exterior and could be sawed apart or wedged apart. Once remanufacturers separated the developer roller from the toner hopper, the remanufacturer could easily access the components in the toner hopper and developer roller housing and could easily reseal the toner hopper.
The HP 9000 has a unique construction. It is anticipated that other OEMs will make toner cartridges of similar construction in the future. The toner hopper and developer roller housing are not welded directly together. Instead they are each separately heat sealed to a specialized seal assembly. This seal assembly has an accordion connector that is heat sealed to an intermediate plate. The intermediate plate is ultrasonically welded to the toner hopper, and the opposite end of the accordion seal is heat sealed to the developer roller housing. The accordion pleats are heat sealed together. The toner hopper and the developer roller housing are thus indirectly connected together. The waste bin section of the HP 9000 attaches in the usual manner to this toner hopper/developer roller housing by use of a pin, and a spring connection. The toner hopper and waste bin are then held in a fixed relationship to one another by two rigid end caps that run the entire width of the cartridge and that are welded onto the toner hopper and the waste bin. The developer roller housing floats relative to the waste bin ensuring that the developer roller and OPC drum maintain a proper relationship. Embedded in one of the end caps near the location of the welds are a variety of electrical contacts that provide the necessary voltages to the different components of the toner cartridge.
The use of the end caps coupled with the electrical connection between one of the end caps, and the sub assembly behind them create unique problems for the remanufacturer. First, end caps must be separated in such a way as to not sever the electrical connections hidden inside them. Secondly, the end caps must be removed in such a way as to allow for reattachment of these end caps.
The seal used in the HP 9000 also presents issues of complexity. Rather than simply heat sealing a seal to a toner hopper, the OEM in the HP 9000 heat seals a metallized film to the toner hopper sealing surface. This metallized film in turn has a tail that is attached to the one end of the seal and extends back over the seal to the other side of the cartridge. The end of the tail is threaded onto a spool. That spool is contained within a housing attached to the toner hopper and concealed within one of the end caps. The toner hopper has electrical contacts on the surface of the toner hopper. These toner hopper contacts are designed to be in electrical contact with a pair of conductive traces on the surface of the OEM seal. When the end-user places the cartridge into the printer, the printer senses whether the seal is in place by sensing whether the electrical connection between the contacts are in place. If there is an electrical connection between both sets of contacts, then the printer will cause the spool to wind, removing the seal from over the toner hopper discharge opening and breaking the electrical connection of the first contact, but not the second contact. If the printer does not sense at least the second contact, then it will not print at all. Therefore, any replacement seal should emulate the electrical characteristics of the OEM seal.
This new construction causes problems in the way the toner hopper and developer roller housing are to be reattached after this assembly. As mentioned above, the OEM heat seals each of these members to an intermediate plate, or an accordion seal. The intermediate plate and accordion seal are destroyed in the process of any separation of the toner hopper from the developer roller housing. In remanufacturing the toner cartridge, it is difficult to maintain the right stack height between the developer roller housing and the toner hopper as well as to firmly adhere the two together.
Additionally, some imaging cartridges, such as the HP 9000, may transmit signals to and receive signals from the printer. For a multiplicity of reasons, it may be advantageous to attenuate or amplify one of the signals being transmitted to or received from the printer. The HP 9000 toner cartridge uses a particular device to sense the toner level when the toner level is below about 8% of capacity. This toner sensing device appears to utilize a signal transmitted from the magnetic roller to a toner sensing plate and transmits, through a contact, a signal to the printer relating to the toner level. During the remanufacturing process of the toner cartridge and replacement of the seal, the voltage level of the toner level signal may be affected. For example, if the electrical characteristics of the replacement seal do not match the electrical characteristics of the original seal, the signal may be transmitted to the printer at a higher voltage level than what is appropriate. In such a situation, the printer may not be able to properly determine the correct toner level due to the higher signal level.
The present method of remanufacturing as described below solves these and other problems associated with remanufacturing cartridges with construction similar to the HP 9000. This method further facilitates rapid and repeatable remanufacturing of these cartridges.